Steinberg's The Missing Link Vol. 1 contains banks, instruments and samples produced by several famous musicians. Well, famous in Germany, at least.
It actually contains a very varied and interesting collection of sounds - dogs growling, gongs, tablas, unbelievably weird machine noises, lots of sound effects, drum loops and grooves, guitars, vintage analogue synths and drum kits, Mellotron sounds and ambient space noises.
The quality is excellent and in spite of the fruitcake factor there are still lots of very useable samples here. The only drawback is the price - £219.